How Do Seedless Fruits Reproduce?

How in the world do they keep growing all these seedless fruits? I see seedless watermelons, grapes, and oranges all the time, but haven’t figured out how they are able to reproduce them without using seeds. Is there a limited supply or are they creating them in a laboratory somewhere? And where did the first one of each type of fruit come from?

**UPDATE** – I think I finally figured out how seedless oranges reproduce! There’s no need to plant new orange trees…they just give birth to baby oranges!